Sediment distribution coefficients (Kd) and bioaccumulation factors (BAF) in biota for natural radionuclides in eastern Black Sea coast of Turkey

Abstract

Germanium (HPGe) detector was used to measure natural (226Ra, 232Th and 40K) radioactivity levels in sediment and seawater samples, and soft tissues of Mediterranean mussels (Mytilus galloprovincialis) of three different sizes, collected from twelve different stations along the coast of Giresun, Trabzon, Rize and Artvin provinces in Eastern Black Sea Region. The average activity concentrations of the sediment and seawater samples collected were 12.65 Bq kg−1 and 3.57 mBq L−1 for 226Ra, 14.25 Bq kg−1 and 4.01 mBq L−1 for 232Th and 294.8 Bq kg−1 and 317.8 mBq L−1 for 40K, respectively. The activity concentrations in soft tissues of three different sized mussel samples altered from 2.45 to 9.59 Bq kg−1 for 226Ra, 2.22–8.59 Bq kg−1 for 232Th and 251.9–382.1 Bq kg−1 for 40K. Moreover, sediment distribution coefficients (Kd) and bioaccumulation factors (BAFw and BAFs) in the mussel samples were calculated. While the bioaccumulation of 226Ra and 232Th from seawater to mussel was observed, the bioaccumulation 40K was observed from sediment to mussel. The ratio of the average concentration of radionuclides in large-sized mussels to that in water and sediment is greater as compared with smaller mussels. Although there were statistically differences (p < 0.05) among mussel sizes according to 232Th levels for activity concentrations, BAFw and BAFs values in soft tissues of the mussel samples, it wasn't observed difference according to 226Ra and 40K levels (p > 0.05).